Celestial certainties

I deliberately planned for this post to be published at the precise moment, in Pacific Time that is, when the solstice occurs.

Welcome to the shortest day of 2016.

Winter Solstice at the Stonehenge Monument in Southern England.

I am now republishing much of what appeared on the EarthSky blog a few days ago.

Late dawn. Early sunset. Short day. Long night. For us in the Northern Hemisphere, the December solstice marks the longest night and shortest day of the year. Meanwhile, on the day of the December solstice, the Southern Hemisphere has its longest day and shortest night. This special day is coming up on Wednesday, December 21 at 10:44 UTC (December 21 at 4:44 a.m. CST). No matter where you live on Earth’s globe, a solstice is your signal to celebrate.

When is the solstice where I live? The solstice happens at the same instant for all of us, everywhere on Earth. In 2016, the December solstice comes on December 21 at 4:44 a.m. CST. That’s on December 21 at 10:44 Universal Time. It’s when the sun on our sky’s dome reaches its farthest southward point for the year. At this solstice, the Northern Hemisphere has its shortest day and longest night of the year.

The word “solstice” comes from the Latin solstitium, meaning “point at which the sun stands still.” Since when has the sun ever moved?! Of course, before Renaissance astronomer Nicolaus Copernicus (aka “super smartypants”) came up with the ‘ol heliocentric model, we all figured that everything revolved around the Earth, sun included. Our continued use of the word “solstice” is a beautiful reminder of just how far we’ve come and provides a nice opportunity to give a tip of the hat to great thinkers who challenged the status quo.